The NDUR Mini Compass with Thermometer is great for anyone's survival bag to help one if the situation arises where they are separated from their group lost their way on the trail or find yourself in a dire drastic survival situation. Can be attached to key chain zippersleeping bag backpack etcFeatures: Compass Thermometer Wind chill table Can be attached to key chain zippersleeping bag backpack etc .3oz (8.5g) 2.5 x 1.75 x .25in (71 x 50 x 7cm)